Not applicable.
Not applicable.
The present invention relates to a device for removing waste material from a blank. More particularly, this invention provides a device for removing waste material from a blank that includes a rotatable cylinder having a number of radially extendable stripping pins for engaging waste material.
The production of a blank, such as an envelope or carton blank, typically occurs in several steps. First, a cutting device cuts a web of paper or other suitable material into a blank portion and waste portion (the waste portion is sometimes referred to as a xe2x80x9cchipxe2x80x9d). The waste portion may be located around the exterior of the blank or may be positioned within the blank if, for example, the end product has a window. Next, a conveying device transports the cut material to a waste removal device that separates the waste portion from the blank portion. Finally, a second conveying device transports the blank portion to a folding machine where it is folded into the end product or to a packing station where a number of blanks are gathered together and processed for outside transportation. This process is usually automated and may be performed by a single machine or by multiple machines.
There are several types of cutting devices. For example, one cutting device operates by stamping a sheet of material with a die to form the blank portion and the waste portion. Another popular device generally comprises two cylinders, each positioned so that their longitudinal axis extends horizontally, with the top cylinder located a short distance above the bottom cylinder. A male die and a female die are coupled to the cylinders so that as the cylinders rotate a passing web is engaged between the dies and cut into a blank portion and a waste portion.
One popular waste separation device resembles the second cutting device described above, that is, it has two cylinders, each positioned so that their longitudinal axis extends horizontally, with the top cylinder located a short distance above the bottom cylinder. The bottom cylinder includes a number of pins extending from its surface and positioned so that when the cylinders rotate and the blank and waste portions pass between the cylinders, the pins penetrate the waste portion. In this manner, the waste material is coupled to the cylinder while the carton blank exits the device. This device is commonly called a pin stripping device.
Several methods are employed to remove the waste portion from the typical two-cylinder pin stripping device. One method involves positioning a plate close to the cylinder containing the pins so that there is a narrow gap between the plate and the tip of the pins. As the cylinder rotates, the leading edge of the plate will slide under the leading edge of the waste material and strip the waste material from the pins. Another method for removing waste from a pin stripping device involves providing a compressed air source coupled to a fluid path that terminates at the surface of the cylinder in close proximity to the pins. After the waste portion is removed from the blank portion and the cylinder has rotated some distance, the compressed air source is engaged to force air through the fluid path to impact on the waste portion and force the waste portion from the pins.
Each of the typical methods for removing waste from a pin stripping device has problems. In the first method, it is difficult to properly position the stripping plate because the plate must be close to and yet not inhibit the pins. If the plate is not positioned properly, it may not catch the leading edge of the waste thereby allowing waste to become jammed between the plate and the cylinder. Additionally, occasionally, one or more portions of waste material may be curled or pressed closely to the bottom cylinder so that the stripping plate will not catch the leading edge of that portion of the waste material. Over time the retained waste will build up and cause the device to jam. In the second method, the waste material may be pressed onto the pins far enough so that the compressed air system will not be strong enough to force the waste portion from the pins. Furthermore, a compressed air source adds complexity to the process in that additional mechanical devices, fittings and tubing are required with the attendant servicing and maintenance.
When material is jammed in the machine, operators may have to shut down the manufacturing process until the problem is corrected. Furthermore, if the waste material is not fully removed during the stripping process, then multiple pieces of waste material may accumulate on the bottom cylinder and thereby reduce the piercing effectiveness of the pins. This unwanted build-up of waste material also can force operators to suspend the manufacturing process. Thus, the use of such pin stripping devices often results in manufacturing delays and increased production costs.
Accordingly, there is a need for a device such as the present invention that will separate waste material from a carton blank without jamming or otherwise causing a delay in the manufacturing process. The present invention also may be utilized to perform various other objectives that will be apparent to those in the art.
The present invention generally encompasses a device for removing waste material from a blank. The invention includes a rotatable stripping pin housing and a stationary cam. The stripping pin housing includes a number of radially extending grooves positioned on its axial surface, with each groove terminating at an aperture located in the stripping pin housing""s circumferential surface. A pin stripping apparatus that includes a radially extending stripping pin and an axially extending cam follower is positioned within each groove. The grooves are sized so that the stripping pin apparatus can slide radially thereby causing the stripping pin to extend from the aperture in the stripping pin housing""s circumferential surface. Each axially extending cam follower is engaged within a cam track formed in the stationary cam, and the cam track is defined at varying distances from the circumferential surface of the cam. In operation, the device is placed so that the stripping pins will engage waste material (and not the blank) as the material passes the device. Thereafter, the stripping pin housing is rotated which causes the cam followers to travel around the cam track so that the radial location of the cam track determines the extent the stripping pins extend from the circumferential surface of the stripping pin housing.